Seizures

Seizures (SEE-zhers) occur when the electrical patterns of the brain are
interrupted by powerful, rapid bursts of electrical energy. A
seizure may cause a person to lose consciousness, to fall down, to jerk
or convulse, or simply to blank out for a few seconds. Infection, injury
or medical problems can cause a seizure. Epilepsy is a disease of the
nervous system characterized by recurring seizures.

KEYWORDS

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Brain Function

Epilepsy

Neurology

Two Stories

Eric's story

As part of his sixth grade study of self-awareness, Eric was assigned to
draw the frames of a film that would show the world as he saw it. Teachers
were puzzled by what Eric drew. One frame showed him pouring milk, the
next frame was completely black, and the next frame showed spilled milk.
In another sequence, Eric drew a teacher calling on him to answer a math
problem, followed by another black frame, and then a picture of the
teacher complaining that Eric was not paying attention. The teachers
realized that Eric's project did show the world as he saw it. The
mysterious black frames were blackouts. Doctors determined that Eric had
absence seizures, a type of seizure that causes a brief loss of
consciousness. Medication successfully controlled Eric's seizures.

Carol's story

All the students in Carol's art class were preparing work for an
art show when Carol stood up and began walking around the room. Looking
like she was in a trance, Carol smacked her lips and tugged at the sleeve
of her dress. About two minutes later, Carol became aware of her
surroundings, only to discover that her classmates were laughing at her
strange behavior. Embarrassed, she ran from the room. Carol had
experienced a complex partial seizure.

*
neurons
are nerve cells. Most neurons have extensions called axons and
dendrites through which they send and receive signals from other
neurons.

What Is a Seizure?

Whether a person is sleeping or awake, millions of tiny electrical charges
pass between neurons
*
in the brain and to all parts of body. These cells "fire,"
or transmit electrical impulses, in an orderly and controlled manner.
Seizures occur when overactive nerve cells send out powerful, rapid
electrical charges that disrupt the brain's normal function. The
disruption can temporarily affect how a person behaves, moves, thinks, or
feels.

Symptoms of a seizure can include combinations of the following:

twitching and tingling in part of the body (for example, fingers and
toes)

muscle spasms spreading to arms and legs

hallucinations

intense feeling of fear or of familiarity (sometimes called deja vu)

a peculiar sensation, sometimes called an aura, immediately before the
seizure (for example, seeing a flashing light or sensing strange odors)

loss of consciousness.

How Do Seizures Differ?

There are two kinds of seizure disorders: an isolated seizure that occurs
only once, and epilepsy (EP-i-lep-see). Epileptic seizures occur more
than
once, and they occur over a period of time. In both epilepsy and isolated
seizures, the seizure may have different symptoms or characteristics
depending on where it begins in the brain and how the electrical discharge
spreads across the brain. Seizures can be generalized or partial.

Generalized seizures

Generalized seizures affect nerve cells throughout the cerebral cortex
(the cauliflower-like outer portion of the brain), or all of the brain.
Generalized seizures often are hereditary, which means they run in
families. They may also be caused by imbalances in a person's
kidney or liver function, or in their blood sugar.

The most common generalized seizures are:

Generalized tonic-clonic seizure (formerly called grand mal seizure):
In the tonic phase of this seizure, people often lose consciousness,
drop to the ground, and emit a loud cry as air is forced over their
vocal cords. In the clonic phase, body muscles contract all at once or
in a series of shorter rhythmic contractions, causing thrashing motions.
Usually, this kind of seizure lasts for about one or two minutes and is
followed by a period of relaxation, sleepiness, and possibly a headache.

Absence seizure (formerly called petit mal seizure):
Loss of consciousness in this seizure is often so brief (usually 10 to
30 seconds) that a person does
not
even change positions. The person may display a blank stare, rapid
blinking, or chewing movements. Facial or eyelid muscles may jerk
rhythmically. Absence seizures may be inherited and usually are seen for
the first time in children between the ages of 6 and 12.

Infantile spasms:
This type of seizure occurs before age 4 and may cause a child to
suddenly flex the arms, thrust the trunk forward, and extend the legs.
The seizure lasts only a few seconds, but
can
recur several times a day.

Atonic seizures:
Also seen primarily in children, these seizures cause a complete loss
of muscle tone and consciousness, which means they pose a serious risk
of injury due to falling.

Myoclonic seizures:
Brief seizures characterized by quick jerking movements of one limb or
several limbs. The person experiencing the seizure does not lose
consciousness.

Febrile seizures:
These seizures occur in infancy or childhood and cause a child to lose
consciousness and convulse. The seizures are accompanied by a high fever
and they are described as either simple or complex. Simple febrile
seizures account for about 85 percent of febrile seizures. They occur
once in 24 hours and last less than 15 minutes. Complex febrile seizures
last more than 15 minutes or occur more than twice in 24 hours.

Partial seizures

Simple partial:
The seizure-related brain messages remain very localized, and the
patient is awake and alert. Symptoms vary depending on what area of the
brain is involved. They may include jerking movements in one part of the
body, emotional symptoms such as unexplained fear, an experience of
peculiar smells, or nausea.

Complex partial:
A person loses awareness of surroundings and is unresponsive or only
partially responsive. There may be a blank stare, chewing movements,
repeated swallowing, or other random activity. After the seizure, the
person has no memory of the experience. In some cases, the person may
become confused, begin to fumble, to wander, or to repeat inappropriate
words or phrases.

What Causes A Seizure?

A seizure generally is easy to recognize, but finding the cause can be
extremely difficult. Doctors begin with a thorough physical examination.
They try to determine if the person has experienced other seizures or has
a family history of seizures. Physicians also want to know if the patient
has experienced an aura
*
, because that can help establish the location in the brain of the
seizure. They also will note the person's age and the nature of the
movements the person made during the seizure.

An electroencephalogram (e-LEK-tro-en-SEF-a-lo-gram), commonly known as an
EEG, records electric currents in the brain and can track abnormal
electrical activity. Doctors may also look for structural brain
abnormalities using other types of scans, including computerized
tomography (CT) and magnetic resonance imaging (MRI). In some research
centers, positron emission tomography (PET) is used to identify areas of
the brain that are producing seizures.

A lumbar puncture, sometimes called a spinal tap, can detect infection.
The procedure requires that a physician carefully insert a thin needle
between two vertebrae (bones) in the patient's spine and draw out a
small amount of cerebrospinal fluid (CSF). The fluid is analyzed for the
presence of bacterial or viral infections, tumors, or blood disorders that
might provide a clue to the cause of the seizure.

*
aura
is a warning sensation that precedes a seizure or other neuro-logic
disorder.

Seizures are associated with the following diseases and conditions:

Epilepsy, a disorder of the nervous system characterized by seizures
that occur more than once and over a period of time.

Head trauma that damages the brain.

Loss of oxygen caused by birth trauma, carbon monoxide poisoning, or
near drowning.

Brain infections, such as meningitis or encephalitis.

Brain tumor.

Stroke.

Toxic (poisonous) agents, including drug abuse or ingestion of poisons
such as lead, alcohol, or strychnine.

Eclampsia or toxemia, which may occur during pregnancy and is
characterized by high blood pressure, protein in the urine, and fluid
retention.

It is important to remain calm and not to panic when someone has a
seizure. An adult usually will ask if the person has epilepsy. If the
person is unable to communicate, an adult will check for a medical
identification bracelet or tag that carries information about the
underlying cause of the seizure.

User Contributions:

What could be causing seizures in a two year old child? and can seizures cause a child to start limping and fail to walk? When my nephew has a seizure his right side stiffens and he makes a coughing noise as if he is choking for about two minutes. However he is now failing to walk. What could be wrong with him?

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